平面的なキラルクロミウムカルボニルアレン複合体のプロパルギルカチオンを代用したダイアステロ選択的プロパルギレーション
A Netz1, K Polborn, T J Müller
1Department Chemie (Organische Chemie) der Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), D-81377 Munich, Germany.
Journal of the American Chemical Society
|July 27, 2001
まとめ
オーガノメタリック電ophiles,特に (arene) Cr CO 3 置換アルファ-プロパルギルカチオン,プロパルギル誘導体の高度にダイアステロ選択的合成を可能にします. この方法は,有機合成におけるステレオ化学的制御に不可欠な構成の保持を証明しています.
科学分野:
- 有機金属化学 有機金属化学
- オーガニック・シンセシス オーガニック・シンセシス
- ステレオ化学 ステレオ化学
背景:
- 平面的なキラルな有機金属化合物は,ユニークな反応性を提供します.
- アルファプロパルギルアセテートは,汎用性の高い合成中間物質です.
- ルイス酸媒介のイオン化は,重要な変換である.
研究 の 目的:
- キラルアルファ-プロパルギルアセテートのイオン化を研究するために.
- 結成された有機金属カチオンへの核性添加を調査する.
- プロパルギル誘導体の地域およびダイアステロセレクティブ合成を達成するために.
主な方法:
- ルイス酸を用いた (アレン) Cr ((CO)) ((3)) 置換アルファプロパルギルアセテートのイオン化.
- 生成されたアルファ-プロパルギルカチオンを様々なヌクレオフィル (S,N,O,C) で核愛的に捕獲する.
- 結晶構造の決定を用いた立体化学分析.
主要な成果:
- 安定した (arene) Cr (((CO)) ((3) 置換されたアルファ-プロパルギュリケーションが形成された.
- プロパルギル誘導体の地域および高度にダイアステロ選択的形成 (44-90%の収量, dr 70:30 から >99:1).
- カチオンのプロパルギレーションは,プロパルギルの中心部での構成の保持とともに進行した.
結論:
- オーガノメタリックカチオンの構成的安定性は,ダイアステレオ選択性にとって重要である.
- S(N) 1メカニズムによるin situイオン化は,ダイアステレオ選択性の喪失につながります.
- この方法論は,複雑なプロパルギル化合物のステレオ制御合成のための強力な経路を提供します.
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